I also believe the ESR for standard aluminum electrolytics goes way up at
low temperatures. If there is substantial ripple current, as in a switching
power supply, the I squared R losses will cause the core to overheat,
spewing electrolyte and launching the can like a projectile. Quite
impressive the first time you see it (I highly recommend safety glasses).
Organic polymer Aluminum electrolytics are much better behaved at low and
high temperatures and have even lower ESR's so you often can use smaller
capacitors. In addition, they do not dry out, as all standard Aluminums
will (that's Aluminium for my Euro colleagues). They also happen to cost
three to ten times as much but they beat the heck out of tantalums for
equivalent price. My dos centavos, anyway.
This is OT, but what is the Euro equivalent of two cents? Is there a coin
for 1/100th of a Euro? If so do Europeans regard it with the same reverence
that we have for our pennies? For instance, many stores here have bowls on
the cash register where customers can leave their valuable pennies rather
than waste the effort of putting them into their pockets.
Regards,
Seth Goodman
Goodman Associates, LLC
tel 608.833.9933
fax 608.833.9966
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Wright, Michael D.
Sent: Wednesday, April 03, 2002 10:33 AM
To: [log in to unmask]
Subject: Re: [TN] Aluminium Electrolytics
Murata, at http://www.murata.com have a good article on this subject. Mainly
the reason is, that the aluminum electrolytic will loose 50% of the rated
capacitance a -40 degrees C. At -55C it is worse. This then also is true for
industrial applications. I just looked for the article that I am referring
to and couldn't find it, so I am attaching it.
Michael Wright
Sr. Engineer
ITT Cannon
952-974-5813
-----Original Message-----
From: DUTTON Phil [mailto:[log in to unmask]]
Sent: Tuesday, April 02, 2002 1:48 AM
To: [log in to unmask]
Subject: [TN] Aluminium Electrolytics
Hello Technetters,
Mil-STD-5400 para 4.3.8.2 says that aluminium electrolytic capacitors shall
not be used in airborne electronic equipment.
Can anyone please explain why this is so?
thanks,
Phil.
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